Forward link power control of multiple data streams transmitted to a mobile station using a common power control channel

ABSTRACT

A method and apparatus for controlling transmit power levels of a plurality of different data streams transmitted from at least one base station to a mobile station in a mobile radio communication system is described. A stream of power control commands is formed at the mobile station in accordance with either the first or second received data stream. A power control signal is formed at the mobile station from the first stream of power control commands and transmitted to the base station.

This application is a continuation of application Ser. No 09/288,262,filed Apr. 8, 1999, now U.S. Pat. No. 6,249,683.

BACKGROUND

I. Field

This invention relates to the field of communications systems and, inparticular, to a method for controlling the transmission power level ofmultiple data streams sent from one or several base stations to a mobilestation in a mobile radio telecommunication system.

II. Prior Art

In a mobile telephone communication system, one or several base stationstransmit information, such as voice information, or data, or both to amobile station. Each base station supports one or several sectors. Forexample in EIA/TIA-95-A CDMA systems it is common that each base stationsupports three individual sectors, with each sector transmittingdifferent information. Voice and data transmissions from a base stationto one or more mobile stations typically occur on a forward link trafficchannel. A mobile station receives the information from the forward linktraffic channel, decodes the information, and determines a frame errorrate associated with the decoded information. The frame error rate ofthe decoded information can be adversely affected by, for example,fading conditions in the forward link channel. Furthermore a trafficchannel can be transmitted from several base stations or several sectorsof the same base station. The mobile station will then combine thesignals from the different sectors for improved decoding, in a processthat is often referred to in the prior art as soft-handoff. The set ofbase station sectors transmitting the same data signal is usually namedan “active set”. It will be understood by those skilled by the art thatthe term soft handoff refers to soft handoff between different basestations as well as soft handoff between different sectors of the samebase station.

In some mobile radio communication systems such as, for example, mobileradio systems that use code division multiple access (CDMA) modulation,the frame error rate at the mobile station is used to control thetransmit power level sent to the mobile on the forward link trafficsignal. For example, in such systems a desired ratio of signal to noisepowers is derived from the desired frame error rate. An estimate of theactual signal to noise ratio received by the mobile is then used togenerate a stream of power control commands that is sent from the mobilestation back to the base stations in the active set. Each power controlcommand in the stream causes the base station to either increase (by,for example, 1 dB), decrease (by, for example, 1 dB) or hold constantthe transmit power sent to the mobile station on the forward linktraffic channel.

Using such a power control system allows the mobile station to cause thebase station to increase the transmit power to compensate for conditionssuch as a fade. Likewise, the power control system permits the basestation to save power when the channel conditions are more favorable anda predetermined error rate can be maintained using a lower transmitpower.

In modern mobile telephone communication systems, several data streams(e.g., fax transmissions, internet transmissions, voice calls etc.) canbe transmitted to a mobile station concurrently. In systems such as CDMAsystems, the transmission of such data streams can occur on the sameforward link traffic channel (i.e., frequency channel). In such cases,each data stream (e.g., voice, fax, internet, etc.) transmitted from aparticular base station to the mobile station on a given forward link ismodulated using a different spreading code often called a Walsh codethat permits each data stream to be separately demodulated at the mobilestation. Different base stations can transmit on the forward link withthe same spreading code when they utilize a different scrambling code(often called a PN code).

Where multiple data streams are transmitted from one or several basestations to a mobile station on one or several forward links, thetransmit power level of each of the data streams should be controlled asdescribed above. However, sending a separate stream of power controlcommands on the reverse link from the mobile station back to each basestation in order to control the transmit power of each data streamresults in a substantial increase in system overhead.

Thus, it would be desirable to provide a system for forward link powercontrol that minimized the overhead required to send power controlcommands from the mobile station back to a base station in cases wherethe base station is transmitting multiple data streams to the mobilestation.

SUMMARY

The present invention is directed to a method and apparatus forcontrolling transmit power levels of a first data stream transmittedfrom each base station in a first active set of base stations to amobile station in a mobile radio communication system, and forcontrolling transmit power levels of a second data stream transmittedfrom each base station in a second active set of base stations to themobile station.

In a first embodiment, a stream of power control commands is formed atthe mobile station for each base station in either the first or secondactive set in accordance with either the first and/or second receiveddata stream from each such base station. A power control signal isformed at the mobile station by interleaving the streams of powercontrol commands, and the interleaved stream of power control commandsis then transmitted to the base stations in the first and second activeset. A received stream of power control commands is formed bydeinterleaving the received power control signal at a given base stationin the first and second active sets, and the transmit power levels ofthe first and second data streams from the given base station are bothcontrolled in accordance with the received stream of power controlcommands. Thus, in this embodiment, a single stream of power controlcommands is used to control the transmit power levels of multipledifferent data streams (e.g., a voice data stream and a fax data stream)transmitted to a mobile station from a common base station.

In accordance with a further aspect of the embodiment set forth above,the second active set of base stations may be a subset of the firstactive set of base stations. In this case, the power control stream foreach base station that is in the first active set but not in the secondactive set will be formed only in accordance with the first data streamfrom such base station.

In accordance with a still further embodiment, the present inventionuses a single interleaved power control signal to transmit multiplepower control command streams to each base station in both the first andsecond active sets, wherein each of the power control command streams isused to control the transmit power of a different data stream sent fromeach base station to the mobile station. In this embodiment, first andsecond data streams are transmitted from each base station in the firstand second active sets and received at the mobile station. A stream ofpower control commands is formed at the mobile station in accordancewith the first received data stream from each base station in the firstactive set, and a stream of power control commands is formed at themobile station in accordance with the second received data stream fromeach base station in the second active set. A power control signal isnext formed at the mobile station by interleaving the streams of powercontrol commands, and the interleaved power control signal istransmitted from the mobile station to each base station in the firstand second active sets. First and second received streams of powercontrol commands are formed at a given base station in the first andsecond active sets by deinterleaving the received power control signalat the given base station. The transmit power level of the first datastream is then controlled from the given base station in accordance withthe first received stream of power control commands, and the transmitpower level of the second data stream is controlled from the given basestation in accordance with the second received stream of power controlcommands.

In accordance with a further aspect of the embodiment set forth above,the second active set of base stations may be a subset of the firstactive set of base stations. In this case, the power control stream foreach base station that is in the first active set but not in the secondactive set will be formed only in accordance with the first data streamfrom such base station.

In accordance with a still further aspect, the signal strengthmeasurements of two corresponding data streams transmitted to a mobilestation from first and second base stations are examined in order todetermine the power control commands used for controlling the transmitpower of one (or both) of the two corresponding data streams transmittedfrom the two base stations. This aspect of the invention thus usesinformation about the signal strength of a data stream transmitted to amobile station from a first base station for generating power controlcommands used for controlling the transmit power of a corresponding datastream transmitted to the mobile station from a second (different) basestation. A first data stream is transmitted from first and second basestations to the mobile station, and a second data stream is transmittedfrom the first base station to the mobile station. In this embodiment,the transmit power level of the first data stream from the first basestation is then controlled at the mobile station by monitoring thesignal quality of the first data stream received from the first basestation as well as the signal quality of the first data stream receivedfrom the second base station. Similarly, the transmit power level of thefirst data stream from the second base station is controlled at themobile station by monitoring the signal quality of the first data streamreceived from the second base station as well as the signal quality ofthe first data stream received from the first base station.

In accordance with yet a still further aspect, the signal strengthmeasurements of two corresponding data streams transmitted to a mobilestation from first and second base stations are examined in order todetermine the power control commands used for controlling the transmitpower of one (or both) of the two corresponding data streams transmittedfrom the two base stations. This aspect of the invention thus also usesinformation about the signal strength of a data stream transmitted to amobile station from a first base station for generating power controlcommands used for controlling the transmit power of a corresponding datastream transmitted to the mobile station from a second (different) basestation. A first data stream is transmitted from first and second basestations to the mobile station, and a second data stream is transmittedfrom the first base station to the mobile station. In this embodiment,the transmit power level of the first data stream from the second basestation is then controlled at the mobile station by monitoring thesignal quality of the first data stream received from the first basestation as well as the signal quality of the first data stream receivedfrom the second base station. The transmit power levels of the first andsecond data streams from the first base station are controlled at themobile station by monitoring the signal quality of the second datastream received from the first base station.

The aspects of the invention discussed in the two paragraphs immediatelyabove can be generalized such that the system uses different signalstrengths from corresponding data streams transmitted to a mobilestation from a first active set of base stations for generating powercontrol commands used for controlling the transmit power of thecorresponding data streams transmitted to the mobile station from eachbase station in the first active set. In this more general embodiment,the first data stream is transmitted from base stations in the firstactive set to the mobile station, and a second data stream istransmitted from base station(s) in a second active set of one or morebase stations to the mobile station. A first set of power controlcommand streams is then formed at the mobile station and transmitted tothe base stations in the first active set, wherein each stream of powercontrol commands in the set is determined in accordance with the firstdata streams received from all base stations in the first active set ofbase stations. The first and second base stations discussed in the twoparagraphs immediately above would be included in the first active setof base stations, the second base station would be included in thesecond active set of base stations, and the second active set of basestations may or may not be a subset of the first active set of basestations.

In a further alternate embodiment, the first stream of power controlcommands is formed at the mobile station in accordance with the firstand second data streams received at the mobile station only from thebase stations in the second active set. The second stream of powercontrol commands is formed at the mobile station in accordance with thefirst data streams or second data streams or both data streams receivedat the mobile station from the base stations in the first active set butnot in the second active set. The mobile station then forms aninterleaved power control signal by interleaving the first and secondstreams of power control commands, and the interleaved power controlsignal is transmitted from the mobile station on the reverse link. Theinterleaved power control signal is received at both the base stationsin the first and second active sets. The base stations form a firstreceived stream of power control commands by deinterleaving the receivedinterleaved power control signal, and a second received stream of powercontrol commands by deinterleaving the received interleaved powercontrol signal. The transmit power level of the first and second datastreams transmitted by the base stations in the second active set isthen controlled in accordance with the first received stream of powercontrol commands, and the transmit power level of the first data streamtransmitted by the base stations in the first active set but not in thesecond active set is controlled in accordance with the second receivedstream of power control commands.

In accordance with a still further embodiment where the communicationsystem includes first and second active sets, the first data stream istransmitted from the base stations in the first active set to the mobilestation, and the second data stream is transmitted from the basestations in the second active set to the mobile station. In thisembodiment, the second active set is a subset of the first active set. Afirst stream of power control commands is formed at the mobile stationin accordance with the first data stream received at the mobile stationfrom the base stations in the first active set. A second stream of powercontrol commands is formed at the mobile station in accordance with thefirst data stream or second data stream or both data streams received atthe mobile station from the base stations in the second active set. Themobile station then forms an interleaved power control signal byinterleaving the first and second streams of power control commands, andthe interleaved power control signal is transmitted from the mobilestation to all the base stations in both active sets. The interleavedpower control signal is received at base stations in both the first andsecond active sets. The base stations form a first received stream ofpower control commands by de-interleaving the received interleaved powercontrol signal, and a second received stream of power control commandsby de-interleaving the received interleaved power control signal. Thetransmit power level of the first and second data streams transmitted bythe base stations that are in the second active set is controlled byusing the commands of the first stream or a combination of both streamsof power control commands. The transmit power level of the first datastream transmitted by the base stations that are in the first active setbut not in the second active set is controlled in accordance with thefirst received stream of power control commands or a combination of thefirst and second received streams of power control commands.

This previous embodiment is particularly useful when the second streamof data is intermittent and only transmitted from a subset of the basestations in the first active set.

In a further embodiment where the radio telephone communication systemincludes different first and second active sets, the first data streamis transmitted from the base stations in the first active set to themobile station and the second data stream is transmitted from the basestations in the second active set to the mobile station. A single streamof power control commands is then formed at the mobile station inaccordance with the first data stream received from the base stations inthe first active set. The mobile station then forms a power controlsignal with the power control commands, and the power control signal istransmitted from the mobile station to all the base stations in bothactive sets. The power control signal is received at base stations inboth the first and second active sets. The base stations in the firstactive set and the base stations in the second active set form areceived stream of power control commands by decoding the received powercontrol signal. The transmit power level of the first data streamtransmitted by the base stations in the first active set and thetransmit power level of the second data stream transmitted by the basestations in the second active set is then controlled in accordance withthe received stream of power control commands. The difference intransmitted power between the first and second data stream is adjustedby means of a separate mechanism. For example a message sent time totime from the mobile station to the base stations or an outer loop basedon the QoS (Quality of Service) currently measured and the desired QoSof the second data stream after decoding by the mobile station. This QoScould be a frame error rate or other.

In an alternate embodiment of the previous embodiment, the power controlcommands are generated based on both the first and second data streamsreceived at the mobile station.

In the above embodiments, the mobile station preferably forms eachstream of power control commands by monitoring either a frame error rateor a signal-to-noise ratio associated with a given received data stream.Furthermore, the first and second streams of power control commands arepreferably generated in accordance with an interleaving pattern, and thecommands from each stream are only generated and inserted when requiredby the interleaving pattern. This ensures that no excess commands aregenerated whose transmission would delay newer commands. This alsoensures that the interleaving process will not delay unnecessarily thepower control commands from one stream or another.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, objects, and advantages of the present invention willbecome more apparent from the detailed description set forth below whentaken in conjunction with the drawings in which like referencecharacters identify corresponding elements throughout and wherein:

FIG. 1A shows a mobile radio station that generates an interleaved powercontrol signal for controlling the transmit power levels of a pluralityof different data streams transmitted to the mobile station from one ormore base stations, in accordance with a preferred embodiment of thepresent invention. In the embodiment of FIG. 1A, the transmit powerlevels of different data streams transmitted to the mobile station fromthe same base station are controlled using a common stream of powercontrol commands included in the interleaved power control signal.

FIG. 1B shows an alternate preferred embodiment of the mobile radiostation of FIG. 1A. In FIG. 1B, the mobile radio station receives aplurality of different data streams from at least one base station, andonly a single data stream from at least one base station.

FIG. 1C shows a mobile radio station that generates an interleaved powercontrol signal for controlling the transmit power levels of a pluralityof different data streams transmitted to the mobile station from one ormore base stations, in accordance with an alternate preferred embodimentof the present invention. In the embodiment of FIG. 1C, the transmitpower levels of different data streams transmitted to the mobile stationfrom the same base station are controlled using different streams ofpower control commands included in the interleaved power control signal.

FIG. 1D shows an alternate preferred embodiment of the mobile radiostation of FIG. 1C. In FIG. 1D, the mobile radio station receives aplurality of different data streams from at least one base station, andonly a single data stream from at least one base station.

FIG. 1E shows an alternate embodiment of the mobile radio station of thepresent invention. In this embodiment, a first data stream istransmitted to the mobile station from at least first and second basestations. The transmit power level of the first data stream from thefirst base station is then controlled at the mobile station bymonitoring the signal quality of the first data stream received from thefirst base station as well as the signal quality of the first datastream received from the second base station. Similarly, the transmitpower level of the first data stream from the second base station iscontrolled at the mobile station by monitoring the signal quality of thefirst data stream received from the second base station as well as thesignal quality of the first data stream received from the first basestation.

FIG. 1F shows a further alternate embodiment of the mobile radio stationof the present invention. In this embodiment, a first data stream istransmitted to the mobile station from at least first and second basestations, and a second data stream is transmitted to the mobile stationfrom the first base station. The transmit power level of the first datastream from the second base station is controlled at the mobile stationby monitoring the signal quality of the first data stream received fromthe first base station as well as the signal quality of the first datastream received from the second base station. The transmit power levelsof the first and second data streams from the first base station arecontrolled at the mobile station by monitoring the signal quality of thesecond data stream received from the first base station.

FIG. 1G shows a further alternate embodiment of the mobile radio stationof the present invention. In this embodiment, a first (common) powercontrol command stream is generated from the first data stream from eachbase station in the second active set and the second data stream fromeach base station in the second active set, and then used forcontrolling the transmit power level of the second data stream from eachbase station in the second active set and the first data stream fromeach base station in the second active set. A second (common) powercontrol stream is generated from the first data stream from each basestation in the first active set and not in the second active set, andthen used for controlling the transmit power level of the first datastream from each base station in the first active set and not in thesecond active set.

FIG. 1H shows a further alternate embodiment of the mobile radio stationof the present invention. In this embodiment, a coarse power controlcommand stream is generated from the first data stream from each basestation in the first active set, and then used for controlling thetransmit power level of the first data stream from each base station inthe first active set and the transmit power level of the second datastream from each base station in the second active set. A fine powercontrol stream is generated from the first data stream from each basestation in the second active set and the second data stream from eachbase station in the second active set, and then used in combination withthe coarse power control command stream for controlling the transmitpower level of the second data stream from each base station in thesecond active set and the first data stream from each base station inthe second active set.

FIG. 1I shows a further alternate embodiment of the mobile radio stationof the present invention. In this embodiment, a coarse power controlcommand stream is generated from the first data stream from each basestation in the first active set and the second data stream from eachbase station in the second active set, and then used for controlling thetransmit power level of the first data stream from each base station inthe first active set and the transmit power level of the second datastream from each base station in the second active set. A fine powercontrol stream is also generated and used in combination with the coarsepower control command stream for adjusting the transmit power level ofthe second data stream from each base station in the second active setthat is also in the first active set.

FIG. 2A shows a base station that receives a plurality of interleavedpower control signals from a plurality of mobile stations, and uses thepower control signals to control the transmit power levels of differentdata streams transmitted to the mobile stations, in accordance with apreferred embodiment of the present invention. In the embodiment of FIG.2A, the transmit power levels of different data streams transmitted tothe same mobile station from the base station are controlled using acommon stream of power control commands included in an interleaved powercontrol signal.

FIG. 2B shows an alternate preferred embodiment of the base station ofFIG. 2A. In FIG. 2B, the base station transmits a plurality of differentdata streams to at least one mobile station, and only a single datastream to other mobile stations on the base station's forward link.

FIG. 2C shows a base station that receives a plurality of interleavedpower control signals from a plurality of mobile stations, and uses thepower control signals to control the transmit power levels of differentdata streams transmitted to the mobile stations, in accordance with analternate preferred embodiment of the present invention. In theembodiment of FIG. 2C, the transmit power levels of different datastreams transmitted to the same mobile station from the base station arecontrolled using different streams of power control commands included inan interleaved power control signal.

FIG. 2D shows an alternate preferred embodiment of the base station ofFIG. 2C. In FIG. 2D, the base station transmits a plurality of differentdata streams to at least one mobile station, and only a single datastream to other mobile stations on the base station's forward link.

FIG. 2E shows a base station that receives a plurality of power controlsignals formed from a plurality of mobile stations of the form shown inFIG. 1F, and uses the power control signals to control the transmitpower levels of first and second data streams transmitted to the mobilestations. In the embodiment of FIG. 2E, the base station is in bothactive sets of the two mobile stations shown as being serviced by thebase station.

FIG. 2F shows a base station that receives a plurality of power controlsignals formed from a plurality of mobile stations of the form shown inFIG. 1F, and uses the power control signals to control the transmitpower levels of first and second data streams transmitted to the mobilestations. In the embodiment of FIG. 2F, the base station is in the firstactive set and not the second active set of the two mobile stationsshown as being serviced by the base station.

FIG. 2G shows a base station that receives a plurality of power controlsignals formed from a plurality of mobile stations of the form shown inFIG. 1G, and uses the power control signals to control the transmitpower levels of first and second data streams transmitted to the mobilestations. In the embodiment of FIG. 2G, the base station is in bothactive sets of the two mobile stations shown as being serviced by thebase station.

FIG. 2H shows a base station that receives a plurality of power controlsignals formed from a plurality of mobile stations of the form shown inFIG. 1G, and uses the power control signals to control the transmitpower levels of first data streams transmitted to the mobile stations.In the embodiment of FIG. 2H, the base station is in the first activeset and not the second active set of the two mobile stations shown asbeing serviced by the base station.

FIG. 2I shows a base station that receives coarse and fine power controlsignals formed from a plurality of mobile stations of the form shown inFIG. 1H, and uses the power control signals to control the transmitpower levels of first and second data streams transmitted to the mobilestations. In the embodiment of FIG. 2I, the base station is in bothactive sets of the two mobile stations shown as being serviced by thebase station.

FIG. 2J shows a base station that receives coarse power control signalsformed from a plurality of mobile stations of the form shown in FIG. 1H,and uses the power control signals to control the transmit power levelsof first data streams transmitted to the mobile stations. In theembodiment of FIG. 2H, the base station is in the first active set andnot the second active set of the two mobile stations shown as beingserviced by the base station.

FIG. 2K shows a base station that receives coarse and fine power controlsignals formed from a plurality of mobile stations of the form shown inFIG. 1I, and uses the power control signals to control the transmitpower levels of first and second data streams transmitted to the mobilestations. In the embodiment of FIG. 2K, the base station is in bothactive sets of the two mobile stations shown as being serviced by thebase station.

FIG. 2L shows a base station that receives coarse power control signalsformed from a plurality of mobile stations of the form shown in FIG. 1I,and uses the power control signals to control the transmit power levelsof first data streams transmitted to the mobile stations. In theembodiment of FIG. 2L, the base station is in the second active set andnot the first active set of the two mobile stations shown as beingserviced by the base station.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1A shows a mobile radio station 100 a that generates an interleavedpower control bit stream 110 for controlling the transmit power levelsof a plurality of different data streams 120, 120 a, 122, 122 a, 124,124 a that are transmitted to the mobile radio station from one or morebase stations. Data streams 120, 122, . . . 124, carry the sameinformation (e.g., the same voice transmission) and are transmitted froma first active set of base stations (i.e., BS1, BS2, . . . BSn). Datastreams 120 a, 122 a, . . . 124 a, carry the same information (e.g., thesame internet or fax transmission) and are simultaneously transmittedfrom a second active set of base stations (i.e., BS1, BS2, . . . BSn).As explained more fully below in connection with various alternativeembodiments, the second active set of base stations may or may not be asubset of the first active set. Data streams 120, 120 a, 122, 122 a,124, 124 a are transmitted to the mobile radio station on, for example,a common frequency band using code division multiple access (CDMA) ortime division multiple access (TDMA) modulation. Multiple data streamsfrom different base stations are used to transmit multiplerepresentations of the same information to the mobile radio stationwhen, for example, the mobile radio station is in a soft handoff betweentwo or more base stations or in cases where diversity signals are usedto achieve better reception at the mobile station. The transmission ofmultiple versions of the same data signal to a given mobile station fromdifferent base stations to perform a soft handoff or to achieve transmitdiversity is well known in the art.

In mobile station 100 a, the data streams 120, 120 a received from BS1are provided to a power control command generator 130 which generates asingle stream of power control commands from the received data streams.In the embodiment of FIG. 1A, power control command generator 130optionally selects either data stream 120 or data stream 120 a (or acombination thereof) to monitor. Thereafter, the power control commandgenerator 130 monitors either the received signal-to-noise ratio or theframe error rate associated with the selected data stream (or the sum ofthe received signal-to-noise ratio or the frame error rate associatedwith both data streams 120, 120 a if the combination is beingmonitored), and generates a series of forward link power controlcommands 140 based on this information. Each power control command instream 140 will, for example, represent a command to BS1 indicating thatBS1 should either increase or decrease the transmit power level used totransmit subsequent frames of data streams 120, 120 a to mobile radiostation 100 a. Deriving such a stream of power control commands usingeither the received signal-to-noise ratio or the frame error rate of asingle received signal is well known in the art. Where a combination ofdata streams 120, 120 a is being monitored, the sum of the receivedsignal-to-noise ratios associated with each data stream is preferablycompared to a threshold representing a desired sum of signal-to-noiseratios expected from the combination of data streams 120, 120 a in orderto generate the stream of power control commands. In the embodiment ofFIG. 1A, a single, common stream of power control commands 140 is thusgenerated for both data streams 120, 120 a using either one of the twodata streams or both streams. This aspect of the invention recognizesthat when multiple data streams are transmitted on a forward linktraffic channel from a base station to a given mobile station, fadingconditions in the traffic channel will likely impact all data streamstransmitted from the base station to the mobile station in a similarmanner and thus a single (or common) stream of power control commandscan be used to control the transmit power of all data streamstransmitted to the given mobile station from the base station.

Referring still to FIG. 1A, the data streams 122, 122 a received fromBS2 are provided to a power control command generator 132 whichgenerates a single stream of power control commands from the receiveddata streams. In the embodiment of FIG. 1A, power control commandgenerator 132 optionally selects either data stream 122 or data stream122 a (or a combination thereof) to monitor. Thereafter, the powercontrol command generator 132 monitors either the receivedsignal-to-noise ratio or the frame error rate associated with theselected data stream (or the sum of the received signal-to-noise ratioor the frame error rate associated with both data streams 122, 122 a ifthe combination is being monitored), and generates a series of forwardlink power control commands 142 based on this information. Each powercontrol command in stream 142 will, for example, represent a command tothe BS2 indicating that the BS2 should either increase or decrease thetransmit power level used to transmit subsequent frames of data streams122, 122 a to mobile radio station 100. Again, deriving such a stream ofpower control commands using either the received signal-to-noise ratioor the frame error rate of a single received signal is well known in theart. Where a combination of data streams 122, 122 a is being monitored,the sum of the received signal-to-noise ratios associated with each datastream is preferably compared to a threshold representing a desired sumof signal-to-noise ratios expected from the combination of data streams122, 122 a in order to generate the stream of power control commands. Inthe embodiment of FIG. 1A, a single, common stream of power controlcommands 142 is generated for both data streams 122, 122 a using eitherone of the two data streams or both streams.

The data streams 124, 124 a received from BSn are provided to a powercontrol command generator 134 which generates a single stream of powercontrol commands from the received data streams. In the embodiment ofFIG. 1A, power control command generator 134 optionally selects eitherdata stream 124 or data stream 124 a (or a combination thereof) tomonitor. Thereafter, the power control command generator 134 monitorseither the received signal-to-noise ratio or the frame error rateassociated with the selected data stream (or the sum of the receivedsignal-to-noise ratio or the frame error rate associated with both datastreams 124, 124 a if the combination is being monitored), and generatesa series of forward link power control commands 144 based on thisinformation. Each power control command in stream 144 will, for example,represent a command to the BSn indicating that the BSn should eitherincrease or decrease the transmit power level used to transmitsubsequent frames of data streams 124, 124 a to mobile radio station100. Again, deriving such a stream of power control commands usingeither the received signal-to-noise ratio or the frame error rate of asingle received signal is well known in the art. Where a combination ofdata streams 124, 124 a is being monitored, the sum of the receivedsignal-to-noise ratios associated with each data stream is preferablycompared to a threshold representing a desired sum of signal-to-noiseratios expected from the combination of data streams 124, 124 a in orderto generate the stream of power control commands. In the embodiment ofFIG. 1A, a single, common stream of power control commands 144 isgenerated for both data streams 124, 124 a using either one of the twodata streams or both streams.

Although data streams from three base stations are shown as beingreceived by mobile station 100 a, it will be understood by those skilledin the art that mobile station 100 could be configured to receive datasignals from more than (or less than) three different base stations.

The power control command streams 140, 142, 144 are provided to amutliplexer 146 which is controlled by an interleaver controller 148.The mutliplexer 146 merges the separate power control command streams140, 142, 144 into a single interleaved power control bit stream 110. Atransmitter 150 transmits the interleaved power control bit stream 110back to the base stations (BS1, BS2 . . . BSn) on a power controlchannel or subchannel.

In a preferred embodiment of the present invention, each base station ina first set of active base stations simultaneously transmits a versionof a first data stream (e.g., signals 120, 122 and 124 in FIG. 1A) tomobile station 100, and each base station in a second set of active basestations simultaneously transmits a version of a second data stream(e.g., signals 120 a, 122 a and 124 a) to mobile station 100. The basestations in each active set are preferably maintained by monitoringpilot signals from base stations in the vicinity of the mobile station100, and then adding or deleting a base station from the active set asthe pilot signal from the base station either rises above or falls belowa threshold. Using pilot signals from base stations for maintaining anactive set of base stations is well known in the art. In the preferredembodiment, the sets of active base stations need not be identical;however, one of the sets of active base stations (e.g., the second set)will typically be a subset of the other set of active base stations(e.g., the first set). As set forth below, in some embodiments of theinvention, the second active set of base stations will not be a subsetof the first active set.

In FIG. 1A, the first set of active base stations used to simultaneouslytransmit versions of the first data stream (e.g., signals 120, 122 and124 in FIG. 1A) to the mobile station was identical to the second set ofactive base stations used to simultaneously transmit versions of thesecond data stream (e.g., signals 120 a, 122 a and 124 a) to the mobilestation. FIG. 1B shows an alternate preferred embodiment of the mobileradio station of FIG. 1A where different sets of active base stationsare transmitting the different data streams to the mobile radio station.In FIG. 1B, mobile radio station 100 b is receiving different datastreams 120, 120 a from BS1, only a single data stream 122 from BS2 andonly a single data stream 124 from BSn. Thus, in FIG. 1B, a first activeset of base stations (i.e., BS1, BS2 and BSn) simultaneously transmitversions of a first data stream (i.e., signals 120, 122 and 124 in FIG.1B) to mobile station 100 b, and a second set of active base stationsformed only of BS1 transmits a second data stream (i.e., signal 120) tomobile station 100 a. The active sets of base stations used fortransmitting the data streams to the mobile station may not be identicalas shown in FIG. 1B when, for example, the mobile station is in a softhandoff between different base stations in the active sets. In theembodiment shown in FIG. 1B, power control command generators 132 a, 134a, respectively monitor data streams 122, 124 in order to generate powercontrol command streams 142, 144 as described above.

FIG. 1C shows a mobile radio station 100 c that generates an interleavedpower control signal 110 for controlling the transmit power levels of aplurality of different data streams transmitted to the mobile stationfrom one or more base stations, in accordance with an alternatepreferred embodiment of the present invention. In contrast to theembodiments of FIGS. 1A and 1B, in the embodiment of FIG. 1C, thetransmit power levels of different data streams transmitted to themobile station from the same base station are controlled using differentstreams of power control commands included in the interleaved powercontrol signal.

Thus, in mobile station 100 c, the data streams 120, 120 a received fromBS1 are provided to a power control command generator 131 whichgenerates a different stream of power control commands for each of thereceived data streams. Power control command generator 131 monitors thereceived signal-to-noise ratio or the frame error rate associated withdata stream 120, and generates a series of forward link power controlcommands 140 a based on this information. Power control commandgenerator 131 also separately monitors the received signal-to-noiseratio or the frame error rate associated with data stream 120 a, andgenerates a separate series of forward link power control commands 140 bbased on this information. Each power control command in stream 140 a or140 b will, for example, represent a command to the BS1 indicating thatthe BS1 should either increase or decrease the transmit power level usedto transmit subsequent frames of data streams 120, 120 a to mobile radiostation 100. Deriving such a stream of power control commands usingeither the received signal-to-noise ratio or the frame error rate of areceived signal is well known in the art.

Referring still to FIG. 1C, the data streams 122, 122 a received fromBS2 are provided to a power control command generator 133 whichgenerates a different stream of power control commands for each of thereceived data streams. Power control command generator 133 monitors thereceived signal-to-noise ratio or the frame error rate associated withdata stream 122, and generates a series of forward link power controlcommands 142 a based on this information. Power control commandgenerator 133 also separately monitors the received signal-to-noiseratio or the frame error rate associated with data stream 122 a, andgenerates a separate series of forward link power control commands 142 bbased on this information. Each power control command in stream 142 a or142 b will, for example, represent a command to the BS2 indicating thatthe BS2 should either increase or decrease the transmit power level usedto transmit subsequent frames of data streams 122, 122 a to mobile radiostation 100.

The data streams 124, 124 a received from BSn are provided to a powercontrol command generator 135 which generates a different stream ofpower control commands for each of the received data streams. Powercontrol command generator 135 monitors the received signal-to-noiseratio or the frame error rate associated with data stream 124, andgenerates a series of forward link power control commands 144 a based onthis information. Power control command generator 135 also separatelymonitors the received signal-to-noise ratio or the frame error rateassociated with data stream 124 a, and generates a separate series offorward link power control commands 144 b based on this information.Each power control command in stream 144 a or 144 b will, for example,represent a command to the BSn indicating that the BSn should eitherincrease or decrease the transmit power level used to transmitsubsequent frames of data streams 124, 124 a to mobile radio station100.

Although data streams from three base stations are shown as beingreceived by mobile station 100 c, it will be understood by those skilledin the art that mobile station 100 c could be configured to receive datasignals from more than (or less than) three different base stations.

The power control command streams 140 a, 140 b, 142 a, 142 b, 144 a, 144b are provided to a mutliplexer 146 which is controlled by aninterleaver controller 148. The mutliplexer 146 merges the separatepower control command streams 140 a, 140 b, 142 a, 142 b, 144 a, 144 binto a single interleaved power control bit stream 110. A transmitter150 transmits the interleaved power control bit stream 110 back to thebase stations (BS1, BS2 . . . BSn) on a power control channel orsubchannel.

In FIG. 1C, the first set of active base stations used to simultaneouslytransmit versions of the first data stream (e.g., signals 120, 122 and124 in FIG. 1C) to the mobile station was identical to the second set ofactive base stations used to simultaneously transmit versions of thesecond data stream (e.g., signals 120 a, 122 a and 124 a) to the mobilestation. FIG. 1D shows an alternate preferred embodiment of the mobileradio station of FIG. 1C where different sets of active base stationsare transmitting the different data streams to the mobile radio station.In FIG. 1D, mobile radio station 100 d is receiving different datastreams 120, 120 a from BS1, only a single data stream 122 from BS2 andonly a single data stream 124 from BSn. Thus, in FIG. 1D, a first activeset of base stations (i.e., BS1, BS2 and BSn) simultaneously transmitversions of a first data stream (i.e., signals 120, 122 and 124 in FIG.1D) to mobile station 100 d, and a second set of active base stationsformed only of BS1 transmits a second data stream (i.e., signal 120) tomobile station 100 d. The active sets of base stations used fortransmitting the data streams to the mobile station may not be identicalas shown in FIG. 1D when, for example, the mobile station is in a softhandoff between different base stations in the active sets. In theembodiment shown in FIG. 1D, power control command generators 133 a, 135a, respectively monitor data streams 122, 124 in order to generate powercontrol command streams 142 a, 144 a as described above.

FIG. 1E shows a mobile radio station 100 e that forms an interleavedpower control bit stream in accordance with an alternate embodiment ofthe present invention. In this embodiment, a first set of active basestations (BS1, BS2, . . . BSn) simultaneously transmit versions of thefirst data stream (e.g., signals 120, 122 and 124) to the mobile station100 e, and a second set of active base stations (BS1, BS2, . . . BSm)simultaneously transmit versions of the second data stream (e.g.,signals 120 a, 122 a and 125) to the mobile station 100 e. Power controlcommand generator 160 generates a separate stream of power controlcommands for controlling the first data stream from each base station inthe first active set. Thus, power control command stream 160 a is usedfor controlling the transmit power of the first data stream from BS1;power control command stream 160 b is used for controlling the transmitpower of the first data stream from BS2; and power control commandstream 160 n is used for controlling the transmit power of the firstdata stream from BSn.

Power control command generator 160 forms each output power controlcommand stream (i.e., streams 160 a, 160 b, 160 n) by monitoring thesignal quality of the first data stream received from multiple basestations in the first active set. Thus, for example, the power controlcommand stream 160 b for controlling the transmit power level of thefirst data stream 122 from the second base station (BS2) is formed bymonitoring the signal quality of the first data stream 122 received fromthe second base station (BS2) as well as the signal quality of the firstdata stream 120 received from the first base station (BS1) and thesignal quality of first data stream 124 received from base station BSn.Similarly, the power control command stream 160 a for controlling thetransmit power level of the first data stream 120 from the first basestation (BS1) is formed by monitoring the signal quality of the firstdata stream 120 received from the first base station (BS1) as well asthe signal quality of the first data stream 122 received from the secondbase station (BS2) and the signal quality of first data stream 124received from base station BSn.

In one embodiment, the algorithm used by power control command generator160 for generating each stream of power control commands 160 a, 160 b, .. . 160 n, is as follows. Initially, power control command generator 160identifies the base station (BS_(highest)) in the first active set thatis providing the highest total signal-to-noise ratio (SNR) for the firstdata stream to mobile station 100 e. Next, a total value representingthe sum of the SNRs for the first data stream received from each basestation in the first active set is compared to a threshold thatrepresents a desired total SNR value that mobile station 100 e expectsto receive from all base stations in the first active set for the firstdata stream. Based on this comparison, power control command generator160 generates a power control command (i.e., a power up, power down orpower hold command) for the first data stream from BS_(highest) and thispower control command (PC_(BS-Highest)) is then sent to BS_(highest)using the power control command stream associated with BS_(highest),i.e., either stream 160 a, 160 b, or . . . , 160 n. Next, the powercontrol command generator 160 generates a first predicted SNR valuerepresenting the sum of the SNRs for the first data stream that mobilestation 100 e expects to receive from all base stations in the firstactive set after PC_(BS-Highest) is processed by BS_(highest). Powercontrol command generator 160 also identifies the base station(BS_(second-highest)) in the first active that is providing the secondhighest total SNR for the first data stream to mobile station 100 e.Thereafter, the first predicted SNR value is compared to the thresholddescribed above, and, based on this comparison, power control commandgenerator 160 generates a power control command (i.e., a power up, powerdown or power hold command) for the first data stream fromBS_(second-highest) and this power control command(PC_(BS-Second-Highest)) is then sent to BS_(second-highest) using thepower control command stream associated with BS_(second-highest), i.e.,either stream 160 a, 160 b, or . . . , 160 n. Next, the power controlcommand generator 160 generates a second predicted SNR valuerepresenting the sum of the SNRs for the first data stream that mobilestation 100 e expects to receive from all base stations in the firstactive set after PC_(BS-Highest) and PC_(BS-Second-Highest) areprocessed by BS_(highest) and BS_(second-highest). Power control commandgenerator 160 also identifies the base station (BS_(third-highest)) inthe first active that is providing the third highest total SNR for thefirst data stream to mobile station 100 e. Thereafter, the secondpredicted SNR value is compared to the threshold described above, and,based on this comparison, power control command generator 160 generatesa power control command (i.e., a power up, power down or power holdcommand) for the first data stream from BS_(third-highest) and thispower control command (PC_(BS-Third-Highest)) is then sent toBS_(third-highest) using the power control command stream associatedwith BS_(third-highest), i.e., either stream 160 a, 160 b, or . . . ,160 n. This process is then repeated as described above in an iterativemanner until power control command generator 160 has generated a powercontrol command for each base station in the first active set.

Referring still to FIG. 1E, power control command generator 162generates a single (common) stream of power control commands 162 a forcontrolling the second data stream from each base station in the secondactive set. Thus, power control command stream 162 a is used forcontrolling the transmit power of the second data stream from BS2, thetransmit power of the second data stream from BS2, and the transmitpower of the second data stream from BSm. Power control commandgenerator 162 forms power control command stream 162 by simultaneouslymonitoring the signal quality of the second data stream received fromall base stations in the second active set. In one embodiment, thealgorithm used by power control command generator 162 for generating thestream of power control commands 162 a is as follows. Power controlcommand generator 162 calculates a total value representing the sum ofthe SNRs for the second data stream received from each base station inthe second active set. This sum is compared to a threshold thatrepresents a desired total SNR value that mobile station 100 e expectsto receive from all base stations in the second active set for thesecond data stream. Based on this comparison, power control commandgenerator 162 generates a power control command (i.e., a power up, powerdown or power hold command) for the second data stream and this powercontrol command is then sent to the base stations in the second activeset using stream 162 a.

The power control command streams 160 a, 160 b, . . . 160 n and 162 aare provided to a mutliplexer 146 which is controlled by an interleavercontroller 148. The mutliplexer 146 merges the separate power controlcommand streams into a single interleaved power control bit stream 110.A transmitter 150 transmits the interleaved power control bit stream 110back to the base stations in the first and second active sets on a powercontrol channel or subchannel.

FIG. 1F shows a mobile radio station 100 f that forms an interleavedpower control bit stream in accordance with a further alternateembodiment of the present invention. In this embodiment, a first set ofactive base stations (BS1, BS2) simultaneously transmit versions of thefirst data stream (e.g., signals 120, 122) to the mobile station 100 f,and a second set of active base stations (BS1) transmit the second datastream (signal 120 a) to the mobile station 100 f. In this embodiment,the transmit power level of the first data stream 122 from the secondbase station (BS2) is controlled at the mobile station 100 f bymonitoring the signal quality of the first data stream 120 received fromthe first base station as well as the signal quality of the first datastream 122 received from the second base station. However, in contrastto the embodiment of FIG. 1E, in this embodiment the transmit powerlevels of the first and second data streams (120, 120 a) from the firstbase station are controlled at the mobile station by monitoring thesignal quality of only the second data stream 120 a received from thefirst base station.

Referring still to FIG. 1F, power control command generator 170 formsoutput power control command stream 170 a by monitoring the signalquality of the first data stream received from multiple base stations inthe first active set. Thus, for example, the power control commandstream 170 a for controlling the transmit power level of the first datastream 122 from the second base station (BS2) is formed by monitoringthe signal quality of the first data stream 122 received from the secondbase station (BS2) as well as the signal quality of the first datastream 120 received from the first base station (BS1). In oneembodiment, the algorithm used by power control command generator 170for generating the stream of power control commands 170 a is as follows.Power control command generator 170 calculates a total valuerepresenting the sum of the SNRs for the first data stream received fromeach base station in the first active set. This sum is compared to athreshold that represents a desired total SNR value that mobile station100 f expects to receive from all base stations in the first active setfor the first data stream. Based on this comparison, power controlcommand generator 170 generates a power control command (i.e., a powerup, power down or power hold command) that is then sent using stream 170a.

Power control command generator 172 monitors either the receivedsignal-to-noise ratio or the frame error rate associated with the seconddata stream 120 a from the first base station, and generates a stream offorward link power control commands 172 a based on this information. Asset forth above, deriving such a stream of power control commands usingeither the received signal-to-noise ratio or the frame error rate of areceived signal is well known in the art.

The power control command streams 170 a and 172 a are provided to amutliplexer 146 which is controlled by an interleaver controller 148.The mutliplexer 146 merges the separate power control command streamsinto a single interleaved power control bit stream 110. A transmitter150 transmits the interleaved power control bit stream 110 back to thebase stations in the first and second active sets on a power controlchannel or subchannel.

FIG. 1G shows a mobile radio station 100 g that forms an interleavedpower control bit stream in accordance with a further alternateembodiment of the present invention. Again, in this embodiment, a firstset of active base stations (BS1, BS2, . . . BSn) simultaneouslytransmit versions of a first data stream to the mobile station 100 g,and a second set of active base stations (BS1, BS2, . . . BSm)simultaneously transmit versions of a second data stream to the mobilestation 100 g. In this embodiment, a first (common) power controlcommand stream 180 a is generated from the versions of the first datastream transmitted from each base station in the second active set(collectively labeled 121) and from the versions of the second datastream transmitted from each base station in the second active set(collectively labeled 123). Power control command stream 180 a is thenused for controlling the transmit power level of the second data streamfrom each base station in the second active set (collectively labeled121) and the first data stream from each base station in the secondactive set (collectively labeled 123). A second (common) power controlstream 182 a is generated from the first data stream from each basestation in the first active set and not in the second active set(collectively labeled 125), and then used for controlling the transmitpower level of the first data stream from each base station in the firstactive set and not in the second active set.

Referring still to FIG. 1G, power control command generator 180 forms asingle (common) output power control command stream 180 a bysimultaneously monitoring the signal quality of traffic signals 121 and123 which respectively represent the first data stream transmitted fromeach base station in the second active set and the second data streamtransmitted from each base station in the second active set. In oneembodiment, the algorithm used by power control command generator 180for generating the stream of power control commands 180 a is as follows.Power control command generator 180 calculates a total valuerepresenting the sum of the signal to noise ratios (SNRs) for the firstdata stream received from each base station in the second active set(i.e., streams 121). This sum is compared to a first threshold thatrepresents a desired total SNR value that mobile station 100 g expectsto receive from all base stations in the second active set for the firstdata stream. Power control command generator 180 also calculates a totalvalue representing the sum of the SNRs for the second data streamreceived from each base station in the second active set (i.e., streams123). This sum is compared to a second threshold that represents adesired total SNR value that mobile station 100 g expects to receivefrom all base stations in the second active set for the second datastream. If, in either of the above comparisons the threshold has notbeen exceeded, power control command generator 180 generates a power-upcommand that is then sent using stream 180 a; alternatively, if ineither of the above comparisons the threshold has been exceeded, powercontrol command generator 180 generates a power-down command that isthen sent using stream 180 a.

Power control command generator 182 forms a single (common) output powercontrol command stream 182 a by simultaneously monitoring the signalquality of traffic signals 125 which respectively represent the firstdata stream transmitted from each base station in the first active setand not in the second active set. In one embodiment, the algorithm usedby power control command generator 182 for generating the stream ofpower control commands 182 a is as follows. Power control commandgenerator 182 calculates a total value representing the sum of the SNRsfor the first data stream received from each base station in the firstactive set and not in the second active set. This sum is compared to athreshold that represents a desired total SNR value that mobile station100 g expects to receive from all base stations in the first active setand not in the second active set for the first data stream. Based onthis comparison, power control command generator 182 generates a powercontrol command (i.e., a power up, power down or power hold command)that is then sent using stream 182 a. The power control command streams180 a and 182 a are provided to a mutliplexer 146 which is controlled byan interleaver controller 148. The mutliplexer 146 merges the separatepower control command streams into a single interleaved power controlbit stream 110. A transmitter 150 transmits the interleaved powercontrol bit stream 110 back to the base stations in the first and secondactive sets on a power control channel or subchannel.

FIG. 1H shows a mobile radio station 100 h that forms an interleavedpower control bit stream in accordance with a still alternate embodimentof the present invention. Again, in this embodiment, a first set ofactive base stations (BS1, BS2, . . . BSn) simultaneously transmitversions of a first data stream to the mobile station 100 h, and asecond set of active base stations (BS1, BS2, . . . BSm) simultaneouslytransmit versions of a second data stream to the mobile station 100 h.In this embodiment, a first (common) power control command stream 184 ais generated from the versions of the first data stream transmitted fromeach base station in the first active set (collectively labeled 177).Power control command stream 184 a contains coarse power controlcommands. As explained more fully below, the coarse power controlcommand stream 184 a is used for controlling the transmit power level ofthe first and second data streams from each base station in the firstand second active sets (collectively labeled 177, 178). A second(common) power control stream 186 a is generated from the first datastream from each base station in the second active set (collectivelylabeled 177 a). Signals 177 a represent a subset of signals 170. Powercontrol command stream 186 a contains fine power control commands. Asexplained more fully below, the fine power control command stream 186 ais used, in combination with the coarse power control command stream 184a, for controlling the transmit power level of the second data streamtransmitted from each base station in the second active set (signals178) and for controlling the transmit power level of the first datastream transmitted from each base station in the second active set(signals 177 a).

Referring still to FIG. 1H, power control command generator 184 forms asingle (common) coarse power control command stream 184 a bysimultaneously monitoring the signal quality of traffic signals 177which represent the first data stream transmitted from each base stationin the first active set. In one embodiment, the algorithm used by powercontrol command generator 184 for generating the stream of power controlcommands 184 a is as follows. Power control command generator 184calculates a total value representing the sum of the SNRs for the firstdata stream received from each base station in the first active set.This sum is compared to a threshold that represents a desired total SNRvalue that mobile station 100 h expects to receive from all basestations in the first active set for the first data stream. Based onthis comparison, power control command generator 184 generates a powercontrol command (i.e., a power up, power down or power hold command)that is then sent using stream 184 a.

In one embodiment, the algorithm used by power control command generator184 for generating the stream of power control commands 184 a is asfollows. Power control command generator 184 calculates a total valuerepresenting the sum of the SNRs for the first data stream received fromeach base station in the first active set. This sum is compared to athreshold that represents a desired total SNR value that mobile station100 h expects to receive from all base stations in the first active setfor the first data stream. Based on this comparison, power controlcommand generator 184 generates a power control command (i.e., a powerup, power down or power hold command) that is then sent using stream 184a.

Power control command generator 186 forms a single (common) fine powercontrol command stream 186 a by simultaneously monitoring the signalquality of traffic signals 177 a and 178 which respectively representthe first data stream transmitted from each base station in the secondactive set and the second data stream transmitted from each base stationin the second active set. In one embodiment, the algorithm used by powercontrol command generator 186 for generating the stream of power controlcommands 186 a is as follows. Power control command generator 186calculates a total value representing the sum of the SNRs for the firstdata stream received from each base station in the second active set(i.e., streams 177 a only). This sum is compared to a threshold thatrepresents a desired total SNR value that mobile station 100 h expectsto receive from all base stations in the second active set for the firstdata stream. Based on this comparison, power control command generator186 generates a power control command (i.e., a power up, power down orpower hold command) that is then sent using stream 186 a.

In an alternate embodiment, a different algorithm is used by powercontrol command generator 186 for generating the stream of power controlcommands 186 a. In this alternate embodiment, power control commandgenerator 186 calculates a total value representing the scaled sum ofthe SNRs for the first data stream received from each base station inthe second active set and the SNRs for the second data stream from eachbase station in the second active set (i.e., streams 177 a and 178).This sum is compared to a threshold that represents a desired total SNRvalue that mobile station 100 h expects to receive from base stations inthe second active set for the first data stream and from base stationsin the second active set for the second data stream. Based on thiscomparison, power control command generator 186 generates a powercontrol command (i.e., a power up, power down or power hold command)that is then sent using stream 186 a.

The power control command streams 184 a and 186 a are provided to amutliplexer 146 which is controlled by an interleaver controller 148.The mutliplexer 146 merges the separate power control command streamsinto a single interleaved power control bit stream 110. A transmitter150 transmits the interleaved power control bit stream 110 back to thebase stations in the first and second active sets on a power controlchannel or subchannel.

FIG. 1I shows a mobile radio station 100 i that forms an interleavedpower control bit stream in accordance with a still alternate embodimentof the present invention. Again, in this embodiment, a first set ofactive base stations (BS1, BS2, . . . BSn) simultaneously transmitversions of a first data stream to the mobile station 100 i, and asecond set of active base stations (BS1, BS2, . . . BSm) simultaneouslytransmit versions of a second data stream to the mobile station 100 i.In this embodiment, a first (common) power control command stream 188 ais generated from the versions of the first data stream transmitted fromeach base station in the first active set (collectively labeled 177) andfrom the versions of the second data stream transmitted from each basestation in the second active set (collectively labeled 178). Powercontrol command stream 188 a contains coarse power control commands. Asexplained more fully below, the coarse power control command stream 188a is used for controlling the transmit power level of the first andsecond data streams from each base station in the first and secondactive sets (collectively labeled 177, 178). A second (common) powercontrol stream 188 b is generated from the first data stream from eachbase station in the first active set (signals 177) and from the seconddata stream from each base station in the second active set (signals178.) Power control command stream 186 b contains fine power controlcommands. As explained more fully below, the fine power control commandstream 188 b is used, in combination with the coarse power controlcommand stream 188 a, for controlling the transmit power level of thesecond data stream transmitted from each base station in the secondactive set and not in the first active set.

Referring still to FIG. 1I, power control command generator 188 formsthe single (common) coarse power control command stream 188 a and thesingle (common) fine power control command stream 188 b bysimultaneously monitoring the signal quality of traffic signals 177, 178which respectively represent the first data stream transmitted from eachbase station in the first active set and the second data stream fromeach base station in the second active set. In one embodiment, thealgorithm used by power control command generator 188 for generating thestream of power control commands 188 a is as follows. Power controlcommand generator 188 calculates a total value representing the sum ofthe SNRs for the first data stream received from each base station inthe first active set (i.e., streams 177 only). This sum is compared to athreshold that represents a desired total SNR value that mobile station100 i expects to receive from all base stations in the first active setfor the first data stream. Based on this comparison, power controlcommand generator 188 generates a power control command (i.e., a powerup, power down or power hold command) that is then sent using stream 188a.

In one embodiment, the algorithm used by power control command generator188 for generating power control command stream 188 b is as follows.First, power control command generator 188 calculates a total valuerepresenting the sum of the SNRs for the second data stream receivedfrom each base station in the second active set (i.e., streams 178only). Next, this sum is adjusted based on the last power controlcommand sent using stream 188 a. More particularly, the power controlcommand generator 180 generates a predicted SNR value representing thesum of the SNRs for the second data stream that mobile station 100 iexpects to receive from all base stations in the second active after theprevious power control command sent on stream 188 a is processed by suchbase stations. The predicted SNR value is then compared to a thresholdthat represents a desired total SNR value that mobile station 100 iexpects to receive from all base stations in the second active set forthe second data stream. Based on this comparison, power control commandgenerator 188 generates a power control command (i.e., a power up, powerdown or power hold command) for the second data stream from each basestation in the second active set, and this power control command is sentusing power control command stream 188 b.

The power control command streams 188 a and 188 b are provided to amutliplexer 146 which is controlled by an interleaver controller 148.The mutliplexer 146 merges the separate power control command streamsinto a single interleaved power control bit stream 110. A transmitter150 transmits the interleaved power control bit stream 110 back to thebase stations in the first and second active sets on a power controlchannel or subchannel.

In an alternate embodiment of the mobile station shown in FIG. 1I, powercontrol command stream 188 a is used for controlling the first andsecond data streams from base stations that are in the first active setand not in the second active set.

Referring now to FIG. 2A, there is shown the components of a basestation 200 a that receives a plurality of interleaved power controlsignals from a plurality of mobile stations (MS1, MS2 . . . MSm), anduses the power control signals to control the transmit power levels ofdifferent data streams transmitted to the mobile stations, in accordancewith a preferred embodiment of the present invention. In the embodimentof FIG. 2A, the transmit power levels of different data streamstransmitted to a mobile station 100 a (as shown in FIG. 1A) from basestation 200 a are controlled using a common stream of power controlcommands included in an interleaved power control signal received atbase station 200 a. Interleaved power control signals 110 received fromthe mobile stations (MS1, MS2, . . . MSm) are provided to power controlsignal demodulation units 210, 212, 214. Demodulation unit 210demodulates an interleaved power control signal 110 transmitted to basestation 200 from a first mobile station (MS1), demodulation unit 212demodulates an interleaved power control signal 110 transmitted to basestation 200 from a second mobile station (MS2), and demodulation unit214 demodulates an interleaved power control signal transmitted to basestation 200 from a further mobile station (MSn). In the embodiment shownin FIG. 2A, each interleaved power stream 110 is formed using a mobilestation such as mobile station 100 a wherein a common stream of powercontrol commands are included in an interleaved power control signal 110in order to control the transmit power levels of different data streamstransmitted to the mobile station from the same base station.

The output of demodulation unit 210 is provided to a demultiplexer 220which deinterleaves the power control signal from the first mobilestation (MS1) in order to extract a power control bit stream 230representative of the stream of power control commands 140 transmittedto base station 200 from the first mobile station (MS1). The powercontrol bit stream 230 is used to control the gain (or transmit powerlevel) of transmitters 240, 242, which respectively transmit first andsecond different data streams 120, 120 a back to the first mobilestation (MS1). The output of demodulation unit 212 is provided to ademultiplexer 222 which deinterleaves the power control signal from asecond mobile station (MS2) in order to extract a power control bitstream 232 representative of a stream of power control commandstransmitted to base station 200 from the second mobile station (MS2).The power control bit stream 232 is used to control the gain (ortransmit power level) of transmitters 244, 246, which respectivelytransmit different data streams back to the second mobile station (MS2).Similarly, the output of demodulation unit 214 is provided to ademultiplexer 224 which deinterleaves the power control signal from afurther mobile station (MSm) in order to extract a power control bitstream 234 representative of a stream of power control commandstransmitted to base station 200 from the further mobile station (MSm).The power control bit stream 234 is used to control the gain (ortransmit power level) of transmitters 248, 250, which respectivelytransmit different data streams back to the further mobile station(MSm). In one embodiment, each of the demodulation units 210, 212, 214is configured to receive an interleaved power control signal on adifferent one of a plurality of power control subchannels, wherein eachof the plurality of power control subchannels is associated with adifferent mobile station in the mobile radio communication system.

Although power control signals from three mobile stations 100 a areshown as being received by base station 200 a, it will be understood bythose skilled in the art that base station 200 a could be configured toreceive power control signals from more than (or less than) threedifferent mobile stations.

FIG. 2B shows an alternate preferred embodiment of the base station ofFIG. 2A. In FIG. 2B, base station 200 b transmits a plurality ofdifferent data streams 120, 120 a to a first mobile station (MS1), andonly a single data stream to other mobile stations (MS2, MSm) on thebase station's forward link. Thus, in base station 200 b, the powercontrol bit stream 232 is used to control the gain (or transmit powerlevel) of a single transmitter 244 which transmits one data stream backto the second mobile station (MS2), and power control bit stream 234 isused to control the gain of a single transmitter 248 which transmits onedata stream back to the further mobile station (MSm). The signal outputby transmitter 244 in FIG. 2B may correspond, for example, to the firstdata stream 122 from BS2 that is provided to the power control commandgenerator 132 a in FIG. 1B, because in the mobile station of FIG. 1Bonly the first data stream (and not the second stream) is provided tomobile station 100 b from BS2.

Referring now to FIG. 2C, there is shown the components of a basestation 200 c that receives a plurality of interleaved power controlsignals from a plurality of mobile stations (MS1, MS2 . . . MSm), anduses the power control signals to control the transmit power levels ofdifferent data streams transmitted to the mobile stations, in accordancewith an alternative preferred embodiment of the present invention. Inthe embodiment of FIG. 2C, the transmit power levels of different datastreams transmitted to a mobile station 100 c (as shown in FIG. 1C) frombase station 200 c are controlled using different streams of powercontrol commands included in an interleaved power control signalreceived at base station 200 c. Interleaved power control signals 110received from the mobile stations (MS1, MS2, MSm) are provided to powercontrol signal demodulation units 210, 212, 214. Demodulation unit 210demodulates an interleaved power control signal 110 transmitted to basestation 200 c from a first mobile station (MS1), demodulation unit 212demodulates an interleaved power control signal 110 transmitted to basestation 200 from a second mobile station (MS2), and demodulation unit214 demodulates an interleaved power control signal transmitted to basestation 200 from a further mobile station (MSn). In the embodiment shownin FIG. 2C, each interleaved power stream 110 is formed using a mobilestation such as mobile station 100 c wherein different streams of powercontrol commands are included in an interleaved power control signal 110in order to control the transmit power levels of different data streamstransmitted to the mobile station from the same base station.

In FIG. 2C, the output of demodulation unit 210 is provided to ademultiplexer 220 which deinterleaves the power control signal from thefirst mobile station (MS1) in order to extract power control bit streams230 a, 230 b which are respectively representative of the streams ofpower control commands 140 a, 140 b transmitted to base station 200 cfrom the first mobile station (MS1). The power control bit streams 230a, 230 b are used to control the gain (or transmit power level) oftransmitters 240, 242, which respectively transmit first and seconddifferent data streams 120, 120 a back to the first mobile station(MS1). The output of demodulation unit 212 is provided to ademultiplexer 222 which deinterleaves the power control signal from asecond mobile station (MS2) in order to extract power control bitstreams 232 a, 232 b which are respectively representative of streams ofpower control commands transmitted to base station 200 b from the secondmobile station (MS2). The power control bit streams 232 a, 232 b areused to control the gain (or transmit power level) of transmitters 244,246, which respectively transmit different data streams back to thesecond mobile station (MS2). Similarly, the output of demodulation unit214 is provided to a demultiplexer 224 which deinterleaves the powercontrol signal from a further mobile station (MSm) in order to extractpower control bit streams 234 a, 234 b representative of streams ofpower control commands transmitted to base station 200 c from thefurther mobile station (MSm). The power control bit streams 234 a, 234 bare used to control the gain (or transmit power level) of transmitters248, 250, which respectively transmit different data streams back to thefurther mobile station (MSm).

FIG. 2D shows an alternate preferred embodiment of the base station ofFIG. 2C. In FIG. 2D, base station 200 d transmits a plurality ofdifferent data streams 120, 120 a to a first mobile station (MS1), andonly a single data stream to other mobile stations (MS2, MSm) on thebase station's forward link. ). The signal output by transmitter 244 inFIG. 2D may correspond, for example, to the first data stream 122 fromBS2 that is provided to the power control command generator 133 a inFIG. 1D, because in the mobile station of FIG. 1D only the first datastream (and not the second stream) is provided to mobile station 100 dfrom BS2.

A communication system operating in accordance with the presentinvention may be formed of one or more mobile stations configured inaccordance with mobile stations 100 a or 100 b that receive data trafficsignals from and transmit interleaved power control signals to aplurality of different base stations configured in accordance with basestations 200 a or 200 b. Alternatively, a communication system operatingin accordance with the present invention is formed of one or more mobilestations configured in accordance with mobile stations 100 c or 100 dthat receive data traffic signals from and transmit interleaved powercontrol signals to a plurality of different base stations configured inaccordance with base stations 200 c or 200 d.

In a still further alternative, a communication system operating inaccordance with the present invention is formed of one or more mobilestations configured in accordance with mobile station 100 e that receivedata traffic signals from and transmit interleaved power control signalsto a plurality of different base stations configured substantially inaccordance with base stations 200 d except, in this embodiment 230, 232a, 234 a and 230 b shown in FIG. 2D would correspond to signals 160 a,160 b, 160 c and 162 produced from a mobile station of the form shown inFIG. 1E.

FIG. 2E shows a base station 200 e that receives a plurality of powercontrol signals formed from a plurality of mobile stations 100 f of theform shown in FIG. 1F, and uses the power control signals to control thetransmit power levels of first and second data streams transmitted tothe mobile stations 100 f. In the embodiment of FIG. 2E, base station200 e is in both active sets of the two mobile stations 100 f shown asbeing serviced by the base station. Power control signals received fromthe mobile stations (MS1, . . . MSx) are provided to power controlsignal demodulation units 210, 214. Demodulation unit 210 demodulates aninterleaved power control signal transmitted to base station 200 e froma first mobile station (MS1), demodulation unit 214 demodulates aninterleaved power control signal 110 transmitted to base station 200 efrom a second mobile station (MSx).

The output of demodulation unit 210 is provided to a demultiplexer 221which deinterleaves the power control signal from the first mobilestation (MS1) in order to extract a power control bit stream 250representative of the stream of power control commands 172 a transmittedto base station 200 e from a first mobile station of the form 100 f (asshown in FIG. 1F). The power control bit stream 250 is used to controlthe gain (or transmit power level) of transmitters 240, 242, whichrespectively transmit first and second different data streams 120, 120 aback to the first mobile station (MS1). The output of demodulation unit214 is provided to a demultiplexer 225 which deinterleaves the powercontrol signal from a second mobile station of the form 100 f (as shownin FIG. 1) in order to extract a power control bit stream 252representative of a further stream of power control commands 172 atransmitted to base station 200 e from the second mobile station (MS2).The power control bit stream 252 is used to control the gain (ortransmit power level) of transmitters 248, 249, which respectivelytransmit first and second different data streams back to the secondmobile station (MS2). In one embodiment, each of the demodulation units210,214 is configured to receive an interleaved power control signal ona different one of a plurality of power control subchannels, whereineach of the plurality of power control subchannels is associated with adifferent mobile station in the mobile radio communication system.

FIG. 2F shows a base station 200 f that receives a plurality of powercontrol signals formed from a plurality of mobile stations 100 f of theform shown in FIG. 1F, and uses the power control signals to control thetransmit power levels of first and second data streams transmitted tothe mobile stations. In the embodiment of FIG. 2F, the base station 200f is in the first active set and not the second active set of the twomobile stations 100 f shown as being serviced by the base station.Demodulation units 210, 214 and demutiplexers 221, 225 functionsubstantially as discussed above in connection with FIG. 2E. However,power control bit stream 260 output by demultiplexer 221 isrepresentative of the stream of power control commands 170 a transmittedto base station 200 e from a first mobile station of the form 100 f (asshown in FIG. 1F). The power control bit stream 260 is used to controlthe gain (or transmit power level) of transmitter 240, which transmitsthe first data stream 122 back to the first mobile station (MS1).Similarly, power control bit stream 262 output by demultiplexer 225 isrepresentative of a further stream of power control commands 172 atransmitted to base station 200 e from a second mobile station of theform 100 f (as shown in FIG. 1F). The power control bit stream 262 isused to control the gain (or transmit power level) of transmitter 242,which transmits a first data stream back to a further mobile station(MSx).

Although power control signals from two mobile stations 100 f are shownas being received by base stations 200 e, 200 f it will be understood bythose skilled in the art that base stations 200 e, 200 f could beconfigured to receive power control signals from more than (or lessthan) two different mobile stations.

FIG. 2G shows a base station 200 g that receives a plurality of powercontrol signals formed from a plurality of mobile stations 200 g of theform shown in FIG. 1G, and uses the power control signals to control thetransmit power levels of first and second data streams transmitted tothe mobile stations. In the embodiment of FIG. 2G, the base station 200g is in both active sets of the two mobile stations 100 g shown as beingserviced by the base station. Demodulation units 210, 214 anddemutiplexers 221, 225 function substantially as discussed above inconnection with FIG. 2E. However, power control bit stream 270 output bydemultiplexer 221 is representative of the stream of power controlcommands 180 a transmitted to base station 200 g from a first mobilestation of the form 100 g (as shown in FIG. 1G). The power control bitstream 270 is used to control the gain (or transmit power level) oftransmitters 240, 242 which transmits the first and second data streamsback to the first mobile station (MS1). Similarly, power control bitstream 272 output by demultiplexer 225 is representative of a furtherstream of power control commands 180 a transmitted to base station 200 gfrom a second mobile station of the form 100 g (as shown in FIG. 1G).The power control bit stream 272 is used to control the gain (ortransmit power level) of transmitters 248, 249, which transmit first andsecond data streams back to a further mobile station (MSx).

FIG. 2H shows a base station 200 h that receives a plurality of powercontrol signals formed from a plurality of mobile stations 100 g of theform shown in FIG. 1G, and uses the power control signals to control thetransmit power levels of first data streams transmitted to the mobilestations. In the embodiment of FIG. 2H, the base station 200 h is in thefirst active set and not the second active set of the two mobilestations 100 g shown as being serviced by the base station. Demodulationunits 210, 214 and demutiplexers 221, 225 function substantially asdiscussed above in connection with FIG. 2E. However, power control bitstream 280 output by demultiplexer 221 is representative of the streamof power control commands 182 a transmitted to base station 200 h from afirst mobile station of the form 100 g (as shown in FIG. 1G). The powercontrol bit stream 280 is used to control the gain (or transmit powerlevel) of transmitter 240, which transmits the first data stream back tothe first mobile station (MS1). Similarly, power control bit stream 282output by demultiplexer 225 is representative of a further stream ofpower control commands 182 a transmitted to base station 200 h from asecond mobile station of the form 100 g (as shown in FIG. 1G). The powercontrol bit stream 282 is used to control the gain (or transmit powerlevel) of transmitter 248, which transmits a first data stream back to afurther mobile station (MSx).

Although power control signals from two mobile stations 100 g are shownas being received by base stations 200 g, 200 h, it will be understoodby those skilled in the art that base stations 200 g, 200 h could beconfigured to receive power control signals from more than (or lessthan) two different mobile stations.

FIG. 2I shows a base station 200 i that receives coarse and fine powercontrol signals formed from a plurality of mobile stations 100 h of theform shown in FIG. 1H, and uses the power control signals to control thetransmit power levels of first and second data streams transmitted tothe mobile stations. In the embodiment of FIG. 2I, the base station 200l is in both active sets of the two mobile stations shown as beingserviced by the base station. Demodulation units 210, 214 anddemutiplexers 221, 225 function substantially as discussed above inconnection with FIG. 2E. However, coarse power control bit stream 290output by demultiplexer 221 is representative of the stream of coarsepower control commands 184 a transmitted to base station 200 i from afirst mobile station of the form 100 h (as shown in FIG. 1H), and finepower control bit stream 292 output by demultiplexer 221 isrepresentative of the stream of fine power control commands 186 atransmitted to base station 200 i from a first mobile station of theform 100 h (as shown in FIG. 1H). The coarse and fine power control bitstreams 290, 292 are used to control the gain (or transmit power level)of transmitters 240, 242 which transmit the first and second datastreams back to the first mobile station (MS1). Similarly, coarse powercontrol bit stream 291 output by demultiplexer 225 is representative ofa further stream of coarse power control commands 184 a transmitted tobase station 200 i from a second mobile station of the form 100 h (asshown in FIG. 1H), and fine power control bit stream 293 output bydemultiplexer 221 is representative of a further stream of fine powercontrol commands 186 a transmitted to base station 200 i from a secondmobile station of the form 100 h (as shown in FIG. 1H). The coarse andfine power control bit streams 291, 293 are used to control the gain (ortransmit power level) of transmitters 248, 249 which transmit first andsecond data streams back to a further mobile station (MSx).

FIG. 2J shows a base station 200 j that receives coarse power controlsignals formed from a plurality of mobile stations 100 h of the formshown in FIG. 1H, and uses the power control signals to control thetransmit power levels of first data streams transmitted to the mobilestations. In the embodiment of FIG. 2H, the base station 200 j is in thefirst active set and not the second active set of the two mobilestations shown as being serviced by the base station. Demodulation units210, 214 and demutiplexers 221, 225 function substantially as discussedabove in connection with FIG. 2E. However, coarse power control bitstream 294 output by demultiplexer 221 is representative of the streamof coarse power control commands 184 a transmitted to base station 200 jfrom a first mobile station of the form 100 h (as shown in FIG. 1H),Only the coarse (and not the fine) power control bit stream 294 is usedto control the gain (or transmit power level) of transmitter 240, whichtransmits the first data stream back to the first mobile station (MS1).Similarly, coarse power control bit stream 295 output by demultiplexer225 is representative of a further stream of coarse power controlcommands 184 a transmitted to base station 200 j from a second mobilestation of the form 100 h (as shown in FIG. 1H). Only the coarse (andnot the fine) power control bit stream 295 is used to control the gain(or transmit power level) of transmitter 248, which transmit a firstdata stream back to a further mobile station (MSx).

Although power control signals from two mobile stations 100 h are shownas being received by base stations 200 i, 200 j, it will be understoodby those skilled in the art that base stations 200 i, 200 j could beconfigured to receive power control signals from more than (or lessthan) two different mobile stations.

FIG. 2K shows a base station 200 k that receives coarse and fine powercontrol signals formed from a plurality of mobile stations 100 i of theform shown in FIG. 1I, and uses the power control signals to control thetransmit power levels of first and second data streams transmitted tothe mobile stations. In the embodiment of FIG. 2K, the base station 200k is in both active sets of the two mobile stations shown as beingserviced by the base station. Demodulation units 210, 214 anddemutiplexers 221, 225 function substantially as discussed above inconnection with FIG. 2E. However, coarse power control bit stream 296output by demultiplexer 221 is representative of the stream of coarsepower control commands 188 a transmitted to base station 200 k from afirst mobile station of the form 100 i (as shown in FIG. 1I), and finepower control bit stream 298 output by demultiplexer 221 isrepresentative of the stream of fine power control commands 188 btransmitted to base station 200 k from a first mobile station of theform 100 i (as shown in FIG. 1H). Only the coarse power control bitstream 296 is used to control the gain (or transmit power level) oftransmitter 240, which transmits the first data stream back to the firstmobile station (MS1). The coarse and fine power control bit streams 296,298 are used in combination to control the gain (or transmit powerlevel) of transmitter 242, which transmits the second data stream backto the first mobile station (MS1). Coarse power control bit stream 297output by demultiplexer 225 is representative of the stream of coarsepower control commands 188 a transmitted to base station 200 k from afurther mobile station of the form 100 i (as shown in FIG. 1I), and finepower control bit stream 299 output by demultiplexer 225 isrepresentative of the stream of fine power control commands 188 btransmitted to base station 200 k from a further mobile station of theform 100 i (as shown in FIG. 1H). Only the coarse power control bitstream 297 is used to control the gain (or transmit power level) oftransmitter 248, which transmits a first data stream back to the furthermobile station (MSx). The coarse and fine power control bit streams 297,299 are used in combination to control the gain (or transmit powerlevel) of transmitter 249, which transmits a second data stream back tothe further mobile station (MSx).

FIG. 2L shows a base station 200 l that receives coarse power controlsignals formed from a plurality of mobile stations 200 i of the formshown in FIG. 1I, and uses the power control signals to control thetransmit power levels of first data streams transmitted to the mobilestations. In the embodiment of FIG. 2L, the base station 200 l is in thesecond active set and not the first active set of the two mobilestations shown as being serviced by the base station. Demodulation units210, 214 and demutiplexers 221, 225 function substantially as discussedabove in connection with FIG. 2E. However, coarse power control bitstream 300 output by demultiplexer 221 is representative of the streamof coarse power control commands 188 a transmitted to base station 200 lfrom a first mobile station of the form 100 i (as shown in FIG. 1I).Only the coarse power control bit stream 300 is used to control the gain(or transmit power level) of transmitter 242, which transmits the seconddata stream back to the first mobile station (MS1). Coarse power controlbit stream 301 output by demultiplexer 225 is representative of thestream of coarse power control commands 188 a transmitted to basestation 200 l from a further mobile station of the form 100 i (as shownin FIG. 1I). Only the coarse power control bit stream 301 is used tocontrol the gain (or transmit power level) of transmitter 249, whichtransmits a second data stream back to the further mobile station (MSx).

Although power control signals from two mobile stations 100 i are shownas being received by base stations 200 k, 200 l, it will be understoodby those skilled in the art that base stations 200 k, 200 l could beconfigured to receive power control signals from more than (or lessthan) two different mobile stations.

Transmission of the interleaved power control signals 110 from a mobilestation to base stations operating in accordance with the presentinvention can be performed by way of a power control channel or a powercontrol subchannel as described above. Each interleaved power controlsignal 110 transmitted to a base station by way of a power controlsubchannel can, for example, be a conventional 800 bits per secondclosed loop power control signal. The interleaving performed by units146, 148 can be performed by a puncturing method well understood bythose skill in the art. In one example, an interleaved power controlsignal 110 is formed using mobile station 100 (FIG. 1A) by interleavingtwo bits of power control information for each of signals 120, 122 and124 with four bits of power control information for each of signals 120a, 122 a and 124 a. This is followed by another two bits of powercontrol information for each of signals 120, 122 and 124 and anotherfour bits of power control information for each of signals 120 a, 122 aand 124 a, and so on. By varying the number of power control bitsallocated to each signal during the interleaving process, the bit ratewithin interleaved signal 110 of the power control bit streamscorresponding to the signals 120, 122, 124 can be made smaller than thatof the power control bit streams corresponding to signals 120 a, 122 a,124 a. The bit rates of the power control bit streams included in theinterleaved signal 110 can also be shifted dynamically based on fadingconditions.

The previous description of the preferred embodiments is provided toenable a person skilled in the art to make and use the presentinvention. The various modifications to these embodiments will bereadily apparent to those skilled in the art, and the generic principlesdefined herein can be applied to other embodiments without the use ofthe inventive faculty. Thus, the present invention is not intended to belimited to the embodiments shown herein but is to be accorded the widestscope consistent with the principles and novel features disclosed.

1. A method for forward link power control of transmissions of at leasttwo data streams to a mobile station using a common power controlchannel, the method comprising: determining a first series of powercontrol command data bits for controlling power level of a first datastream of said least two data streams; determining a second series ofpower control command data bits for controlling power level of a seconddata stream of said least two data streams; multiplexing said first andsecond series of power control command data bits to form a common seriesof power control command data bits; transmitting said common series ofpower control command data bits over said common power control channelfor controlling power levels of transmissions of said least two datastreams to said mobile station.
 2. The method as recited in claim 1wherein said determining said first series of power control command databits includes: comparing receiving quality of said first data stream atsaid mobile station to a first threshold; generating up or down commandfor said first series of power control command data bits based on saidcomparing.
 3. The method as recited in claim 1 wherein said determiningsaid second series of power control command data bits includes:comparing receiving quality of said second data stream at said mobilestation to a second threshold; generating up or down command for saidfirst series of power control command data bits based on said comparing.4. The method as recited in claim 1 wherein said multiplexing includesmultiplexing said first and second series of power control command databits to form said common series of power control command data bits in atime frame of said common power control channel.
 5. The apparatus forforward link power control of transmissions of a least two data streamsto a mobile station using a common power control channel, the methodcomprising: a controller configured for determining a first series ofpower control command data bits for controlling power level of a firstdata stream of said least two data streams, for determining a secondseries of power control command data bits for controlling power level ofa second data stream of said least two data streams, and multiplexingsaid first and second series of power control command data bits to forma common series of power control command data bits; a transmitter fortransmitting said common series of power control command data bits oversaid common power control channel for controlling power levels oftransmissions of said least two data streams to said mobile station. 6.The apparatus as recited in claim 5 wherein said controller furtherconfigured for determining said first series of power control commanddata bits by comparing receiving quality of said first data stream atsaid mobile station to a first threshold, and for generating up or downcommand for said first series of power control command data bits basedon said comparing.
 7. The apparatus as recited in claim 5 wherein saidcontroller further configured for determining said second series ofpower control command data bits by comparing receiving quality of saidsecond data stream at said mobile station to a second threshold, and forgenerating up or down command for said first series of power controlcommand data bits based on said comparing.
 8. The apparatus as recitedin claim 5 wherein said controller further configured for multiplexingsaid first and second series of power control command data bits to formsaid common series of power control command data bits in a time frame ofsaid common power control channel.